Makes NOW() return an UTC date

Closes #843

rdflib/plugins/sparql/sparql.py

@@ -5,6 +5,7 @@
 import datetime
 from collections import Mapping, MutableMapping
 
+import isodate
 from six import text_type, iteritems
 
 from rdflib.namespace import NamespaceManager
@@ -242,7 +243,7 @@ def __init__(self, graph=None, bindings=None, initBindings=None):
             self.graph = graph
 
         self.prologue = None
-        self.now = datetime.datetime.now()
+        self.now = datetime.datetime.now(isodate.tzinfo.UTC)
 
         self.bnodes = collections.defaultdict(BNode)
 

try.py

@@ -0,0 +1,34 @@
+from rdflib.plugins.sparql.operators import custom_function
+
+from rdflib import Graph, URIRef, Namespace, Literal
+from rdflib.plugins.sparql.sparql import SPARQLError
+
+g = Graph()
+foo = URIRef('http://foo')
+g.add((foo, foo, foo))
+
+XF = Namespace('http://xact.ai/fn#')
+
+
+@custom_function(XF.nativeLE)
+def xf_native_le(a, b):
+    if not isinstance(a, Literal) or not isinstance(b, Literal):
+        raise SPARQLError("xf:nativeLE is only implemented on Literals")
+    return Literal(a.toPython() <= b.toPython())
+
+
+@custom_function(XF.nativeAdd)
+def xf_native_add(a, b):
+    print(a, b, Literal(a.toPython() + b.toPython()))
+    if not isinstance(a, Literal) or not isinstance(b, Literal):
+        raise SPARQLError("xf:nativeAdd is only implemented on Literals")
+    return Literal(a.toPython() + b.toPython())
+
+
+for r in g.query(
+        "SELECT * WHERE { BIND(<http://xact.ai/fn#nativeAdd>('P1Y'^^xsd:duration, 'P1Y'^^xsd:duration) AS ?t) ?s ?s ?s }"):
+    print(r)
+
+for r in g.query(
+        "SELECT * WHERE { BIND(NOW() AS ?t) ?s ?s ?s }"):
+    print(r)